Robots sent into a reactor at Japan's Fukushima power plant last week recorded the highest levels of radiation there since it was hit by a tsunami a month-and-a-half ago.  Workers, meanwhile, are using the crudest of measures to stave off a full meltdown: dousing the reactors with millions of litres of water.  Japan's daily struggle to prevent a full-blown disaster may have fallen off the front pages here, but it brings into sharp relief what energy executives say is a moment of truth for Britain.  Nuclear power is at the heart of government plans to reshape our energy infrastructure for a low-carbon world. In June, the government will publish its final plan to get us there.  Based on the initial version, released before Christmas, it will involve a cocktail of big subsidies for nuclear and offshore wind, harsh penalties for coal, and a doubling, at least, of household energy bills.  The electricity market reform is a return to aggressive state intervention - ministers argue the market alone cannot deliver the "green revolution". The scale of the task is on a par with North Sea gas conversion in the late 1960s - only more expensive: ?200 billion, by current estimates.  Increasingly, though, there are concerns the government has got its sums badly wrong. The industry has lobbied frantically for changes to the new market structure but the consultation period has ended. "The ramifications of this will be profound," said a senior industry source. "If we choose to go down this route, the UK will end up with an energy system three to four times more expensive than others and our economy will be rendered uncompetitive, full stop." Consider nuclear power.  Chris Huhne, the energy secretary, ordered a safety review in the wake of the Fukushima disaster.  Mike Weightman, the Nuclear Industry association's chief inspector, is due to publish his provisional report next month before a final one in September.  It is highly unlikely he will produce an authoritative report on nuclear safety while Fukushima remains too radioactive for close examination. Industry insiders are now factoring a delay of two years or more into EDF Energy's plans to build Britain's first new reactor by 2018. Such a delay would be a big problem.  More than 20 coal, oil and nuclear plants will shut over the next decade. If the new generation of nuclear plants is delayed, other power stations would have to be built to fill the gap - probably gas-fired, which would hinder Britain's carbon emission reduction.  and there are other problems.  Ofgem, the regulator, predicted that, in the worst-case scenario, household energy bills could double to ?2,000 a year within a decade. Industry insiders now acknowledge that this figure looks low.  Extra safety for nuclear plants will add to the predicted ?5 billion price tag for each reactor. Ofgem's prediction was based on a world where oil was about $110 a barrel. Last week it closed at $128 - analysts at Barclays Capital predict it could hit $184 by 2020, though new gas finds in america could keep gas prices lower.  To make matters worse, the industry has lost faith in the government. The multi-billion pound investments that companies are being asked to make will be underpinned by subsidies for the more expensive low-carbon technologies. The more firms spend, the bigger their profits. Spending ?200 billion will generate ?10 billion to ?15 billion in additional profit for Britain's big six utilities.  So, companies have been unsettled by chancellor George Osborne's surprise "windfall" tax on North Sea oil firms in the budget.  "The risk for companies is that this scale of investment will lead to rising profits just as consumers are experiencing large increases in their utility bills," said M